Fats are derived from the accumulation of overfed energy in white adipose tissue and the excessive accumulation thereof in white adipose tissue is commonly referred to as obesity. The breakdown of triglycerides into free fatty acid (FFA) and glycerol, e.g., by hormone sensitive lipase (HSL), is referred to as lipolysis.
For improving obesity, a surgical operation, liposuction, is being carried out. Liposuction, which is also known as lipoplasty or liposculpture suction lipectomy, is a cosmetic surgical operation for removing fats from various sites in the body, such as abdomen, thighs, hips, neck, upper arms, and so on. However, there are concerns that liposuction may cause serious side effects, including wounds, swelling, paralysis and burning sensation, a risk of infection in the surgical site; damage to skin or nerves; and puncture wounds in critical organs. In addition, it requires a significant period of time for treatment and recovery; and also there are risks associated with anesthesia because it requires local anesthesia or general anesthesia during the surgical procedure.
Phosphatidylcholines (PC) are a class of phospholipids that incorporate choline as a headgroup. They are widely found in animals, plants, yeast, and fungi and are also referred to as lecithin or unsaturated lecithin. They are mainly contained in the brain, nerves, blood cells, egg yolk and the like in mammals; and in soybeans, sunflower seeds, wheat germ and the like in plants. Because phosphatidylcholine has four double bonds in its molecule, it is easily oxidized during the preparation or during the storage, thereby the structure thereof being deformed. In order to overcome such disadvantage, the saturated lecithin forms have been developed which are prepared by adding hydrogen to the unsaturated lecithin. US Laid-open Patent Publication No. US 2005/0287199 has disclosed a method for reducing adipose tissue which includes injecting lecithin. In addition, US Laid-open Patent Publication No. US 2016/0339042 has disclosed a method for reducing localized adipose tissue comprising topically administering to a site at or proximate adipose tissue a composition comprising lecithin and bile acid or a salt thereof. However, the topical injection of lecithin for inducing lipolysis leads to side effect problems such as erythema, inflammation, tissue necrosis, edema, dimpling and the like. And also, when a lecithin-containing formulation is stored for a long period of time, it leads to problems such as lowered stability and lipolytic activity.